Shepardus

https://doomwiki.org/wiki/DemWAD01

Here you can find a new SLIGE-generated megawad every day.

Plutonia averages fewer monsters per map than Doom II.

Cool concept with some cute reimaginings of Doom II's levels. Very timely with how Run From It is making the rounds again as a "bad map concept." Incidentally, that gives me some ideas for implementing different timer lengths in vanilla, should you be interested in doing as Meowgi suggested (crush a voodoo doll like in Run From It, or crush a barrel to push a voodoo doll over a line). Regarding the palette changes, I feel like the item pickup flash could be toned down, it feels like the whole screen is fading when picking up a bunch of items (e.g. the beginning of MAP21). I guess the effect was always like that, but I actually notice it more acutely with this palette than with the original one.

I think the question was already sufficiently answered in the first few replies to this thread, but in case you need things repeated: No, GZDoom doesn't work like that, and there isn't a compatibility flag to make it so. Would it be possible to create a mod replicating the effect? Maybe, but I doubt anyone has cared enough to make such a thing, and asking again won't magic it into existence.

If you mean "professional" in the sense of getting paid to do this, then I hate to break it to you, but nobody here is getting paid to be at your beck and call. If you keep treating people here like they exist solely to dispense answers to you, it's no surprise that they'll get tired of doing so.

That's pretty much what Raven was doing for much of its existence.

FYI dsda-doom doesn't depend on SDL2_net anymore.

Ancient Aliens had an article shortly before Doom 2016's release (by the same person who wrote the D2INO article for PC Gamer), though it reads like the author just skimmed the forum post and didn't even download the WAD.

In GZDoom it's Compatibility Options -> Map/Action Behavior -> Use buggier stair building (compat_stairs). I just tested it and having that on does break the stairs. The "Doom (strict)" compatibility mode includes setting that flag on, so as a player I would advise not using "Doom (strict)" compatibility when playing this, since after all this isn't a vanilla Doom WAD ("Boom (strict)" works fine). If you really want to, I think you can force the flag off in MAPINFO. In Boom/MBF-derived source ports it's the "comp_stairs" option. In PrBoom+/Woof/Eternity's compatibility menu (which dsda-doom removed in favor of the OPTIONS lump) it's "Use exactly Doom's stairbuilding method." This is off for complevels 9 and up but should be on for complevel 2, so I'm not sure why you weren't able to reproduce it with complevel 2 (if you were using the TNTCOMP cheat, maybe that doesn't work for this?). I was able to reproduce it by launching the game with complevel 2 and noclipping to the room. I don't fully understand the change (or stairbuilders in general), but the ZDoom wiki says the following: "When looking for all tagged sectors to build stairs, Doom.exe resumed the search with the last sector of the current stair, not the one following the starting sector." TNT MAP30 relies on the vanilla behavior, so if you play that map with complevel 9, the stairs to the red skull key don't rise high enough to reach the key. Rather ironic that TeamTNT's source port breaks their own WAD...

I haven't looked at this specific area, but my first thought is that it's a stair builder behavior that was changed in Boom and ZDoom (TNT MAP30 is a notable example that requires the vanilla behavior to work correctly). There's a compatibility flag related to stair builders, try changing that and see if it makes the difference.

The freshest WAD to be inspired by D5DA since D5DA. Minor bug(?): The windows in MAP32 HoM when using software renderer but show sky when using OpenGL renderer.

Change the "death use action" setting to "reload."